1. Field of the Invention
The present invention relates to a drive control apparatus for a driven machine, such as a motor, controlled according to parameters and to a parameter displaying method in the drive control apparatus for the driven machine.
2. Description of the Background Art
In describing the conventional designs that are relevant as background to the present invention, an inverter apparatus will be employed as an example of a motor drive apparatus for a sewing machine, solely for convenience of description. Of course, the invention will not be limited thereto.
FIG. 14 is a block diagram illustrating a drive control apparatus for a driven machine, e.g., an inverter apparatus, known in the art, wherein the numeral 1 indicates a converter module for rectifying three-phase alternating current, 2 denotes a capacitor for smoothing the rectified output of the converter module 1, 3 represents an inverter module for converting direct current, or the smoothed output of the capacitor 2, into alternating current, and 4 designates a driven machine, e.g., an induction motor, connected to the inverter module 3.
5 indicates a control section for controlling the inverter module 3, 6 denotes a microprocessor, 7 designates a ROM, 8 represents a RAM, 9 indicates an operations unit, and 11 represents non-volatile memory consisting of memory devices which do not lose data if the power of the inverter apparatus is shut off. This non-volatile memory 11 is referred to as a current value storage.
Constants employed to control the induction motor 4, e.g., acceleration time, deceleration time, base frequency and maximum frequency limit, are stored in the non-volatile memory 11 as parameter values. Each of these constants is identified by a corresponding parameter number from a sequence and is stored in the non-volatile memory 11 along with the parameter value.
Generally, there are 20 to 50 types of parameters or constants applicable to the operation of a machine and initial values are set for each of the parameter numbers, before the apparatus is shipped from a factory, by storing appropriate parameter values in the non-volatile memory 11.
12 indicates a gate array, and 13 represents an interface provided between the operations unit 9 and the gate array 12. The operations unit 9 will generate a signal for controlling the motor via inverter module 3. On receipt of a PWM signal transmitted from the operations unit 9 via the interface 13, the gate array 12 provides upper arm/lower arm short-circuit prevention times for the input PWM signal.
14 indicates an amplifier for amplifying the PWM signal which is provided with the upper/lower arm short-circuit prevention time by the gate array 12 so that the signal can drive transistors (upper and lower arm transistors) bridge-connected in the inverter module 3. The ROM 7, the RAM 8, the operations unit 9, an interface 10 and the interface 13 constitute the microprocessor 6. The microprocessor 6, the non-volatile memory 11, the gate array 12 and the amplifier 14 constitute the control section 5.
15 indicates parameter setting apparatus, represents a data display section, and 17 designates a data input section. The parameter setting apparatus 15 consists of the data display section 16 and the data input section 17. The data display section 16 has four seven-segment LED's 16a arranged as shown in FIG. 15 to display a four-digit numeral. The parameter setting apparatus 15 can transfer signals to and from the control section 5 via the interface 10 in the microprocessor 6.
The operation of the conventional apparatus shown in FIG. 14 will now be described. The alternating current input to the converter module 1 is rectified and then input to the capacitor 2 and smoothed there when the smoothed direct current is input to the inverter module 3, it is converted into the alternating current under the control of the PWM signal output from the control section 5, and the alternating current is supplied to the induction motor 4.
The control section 5 reads a program from the ROM 7 and also reads parameter values from the non-volatile memory 11, and the operations unit 9 performs operations using the RAM 8 and generates the PWM signal. The PWM signal generated is input to the gate array 12 through the interface 13. The gate array 12 provides the upper/lower arm short-circuit prevention time for the PWM signal input from the interface 13, and inputs the signal to the amplifier 14. Also, the amplifier 14 amplifies the PWM signal provided with the upper/lower arm short-circuit prevention time, and supplies it to the inverter module 3.
The control section 5 stores the parameter values, which have been input from the data input section 17 of the parameter setting apparatus 15, into the non-volatile memory 11 and drives the induction motor 4 in accordance with the parameter values stored.
The parameter values stored in the non-volatile memory 11 must be rewritten to optimum values according to the drive control characteristics of the induction motor 4, the induction motor 4 to be driven, the load of the induction motor 4, etc. This rewrite is performed from the parameter setting apparatus 15 as described above.
Namely, new parameter data input from the data input section 17 of the parameter setting apparatus 15 is transferred to the operations unit 9 via the interface 10. Subsequently, the new data is written to the non-volatile memory 11 via the operations unit 9, whereby the contents of the non-volatile memory 11 are rewritten.
To examine which of the parameters existing in the non-volatile memory 11 have been updated from the initial factory-set values, it is required to repeat the operation shown as a flowchart in FIG. 16 to check all parameters, using the parameter setting apparatus 15.
A method of examining which parameters have been updated will now be described with reference to the flowchart shown in FIG. 16. Referring to FIG. 16, a parameter number is specified from the parameter setting apparatus 15 at step S1101 to identify the parameter to be read, and the execution progresses to next step S1102. At step S1102, the parameter value of the parameter specified at step S1101 is read from the nonvolatile memory 11, and the processing advances to next step S1103.
At step S1103, the data read at step S1102 is transferred from the operations unit 9 to the parameter setting apparatus 15 via the interface 10 and is displayed on the data display section 16. An operator then verifies the data displayed on the data display section 16 with a factory-set initial value list given in an instruction manual or the like to check whether or not the corresponding parameter has been rewritten.
Which parameter has been rewritten cannot be identified until the steps S1101 to S1103 have been repeated for all parameters.
Since the conventional drive control apparatus for a driven machine, for which the inverter apparatus for drive-controlling the motor may be taken as a typical example, is designed as described above, a factory-set initial value list must be prepared separately, and the operation of reading the parameter and the judgment of whether the parameter read matches said initial value list must be performed manually for all parameters in order to check for any parameter rewritten after the shipment from the factory. This approach clearly is inefficient and subject to human error.
Also, the data display section 16 only displays a four-digit numeral and cannot display the parameter number and parameter value at the same time. Hence, the operator cannot determine which of the parameter values is currently being displayed.
Also, if a wrong setting has been made, it is required to return the parameter value to the initial value, check the initial value, and make a re-setting. However, a return to the initial value was difficult. In addition, when the same settings were to be made to a plurality of driven machines, it was required to make parameter settings for the number of driven machines, taking much time for setting.